depends on the suit really, if it is clearly cut as a woman's then I do not see the point. If it were a man's, then yes she would fit into the definition to a degree. Please note that one definition says "noticeably consistently crosses prevailing social sex-role boundaries" and the other "regularly acts inconsistent...". These are not referring to an occasional outfit. As well, for me at least, I believe that "intent" is very important in determining how a person might fit into the group "transgender" etc... There are many women wearing male cut clothing that have no intent of "looking" or "being" male. Hence they are not TG.
Anyhow, I've put these out there for discussion sake really, no hard and fast rules here. I'm not really sure why people are bothered by the term TG including them. It doesn't say that a CD is transsexual or the like, rather that there are many flavors of what people call transgender.